def __init__(self, Data, band, kpoint_indices):
"""Initialise an instance of the Segment class.
Args:
Data (Data): Data instance initialised from the bandstructure which contains the segment
band (int): the band number of the segment
kpoint_indices (list(int)): the kpoint indices of the segment
Returns:
None.
"""
self.band = band
self.kpoint_indices = kpoint_indices
self.kpoints = np.array([Data.kpoints[k] for k in kpoint_indices
]) # in units 2*pi/angstrom
self.cartesian_kpoints = np.array([
np.dot(k, Data.reciprocal_lattice) for k in self.kpoints
]) # in units 1/Angstrom. Reciprocal lattice includes factor 2*pi.
self.dk_angs = np.linalg.norm(
self.cartesian_kpoints - self.cartesian_kpoints[0], axis=1)
self.dk_bohr = np.divide(
self.dk_angs, angstrom_to_bohr
) # divide as we are in reciprocal space --> units in inverse length
self.energies = np.array(
[Data.energies[band, k] for k in kpoint_indices]) # in units eV
self.dE_eV = self.energies - self.energies[0]
self.dE_hartree = np.multiply(self.energies - self.energies[0],
ev_to_hartree)
if Data.occupancy is not None:
self.occupancy = np.array(
[Data.occupancy[band, k] for k in kpoint_indices])
else:
self.occupancy = None
self.direction = extrema.calculate_direction(self.kpoints[1],
self.kpoints[2])
self.fermi_energy = Data.fermi_energy
self._VBM = Data.VBM
self._CBM = Data.CBM
self.band_type = self._band_type()
def test_calculate_direction_opposite(toy_data_object):
a = toy_data_object.kpoints[1]
b = toy_data_object.kpoints[0]
assert np.allclose(extrema.calculate_direction(a, b), np.array([1, 0, 0]))